:root{
    /* 设置根元素的属性 */
    /* 定义css全局变量 */
    --main-color:#2ab8f5;
    --text-color:#999;
    --title-color:#333;
    background-color: #f7f8fa;
    font-family: "微软雅黑";
}
a{
    text-decoration: none;
}
.clearfix::before,.clearfix::after{
    content:"";
    display: block;
    width:0px;
    height:0px;
    overflow: hidden;
    clear: both;
}